That depends on which Godzilla we're talking about. First, there's the original Gojira from 1954. In his first appearance, it's stated that he was disturbed by underwater hydrogen bomb testing, which subsequently leads to his mutated appearance. read more
He would occasionally fight alongside humanity, but not out of any love, even when he became a hero. If anything, we can conclude that Showa Godzilla’s greatest motivation was protecting the Earth itself. After him comes Heisei Gojira. read more
Godzilla's allegiance and motivations have changed from film to film to suit the needs of the story. Although Godzilla does not like humans, it will fight alongside humanity against common threats. read more
Metphies responds by saying that if Mechagodzilla had defeated Godzilla, the Bilusaludo could have turned it against humanity and conquered the Earth next. Galu-Gu says none of that matters anymore, since Godzilla had forced all three races into the same situation after they all failed to stop him. read more